Refrigerator with Ultraviolet Light Emitting Diode

ABSTRACT

Embodiments of the invention include a sealed compartment and a door disposed on a side of the sealed compartment, and a cooler for cooling an interior of the sealed compartment. At least one light emitting diode configured to emit light having a peak wavelength in the ultraviolet range is positioned to emit ultraviolet light in the sealed compartment.

BACKGROUND

1. Field of Invention

The present invention relates to a refrigerator including ultravioletlight emitting diodes.

2. Description of Related Art

Current methods for reducing or eliminating growth of microbes inrefrigerators used, for example, to store or display perishable food,include reducing the temperature and humidity to create conditions thatreduce or eliminate microbial growth, treating the refrigeratorcompartment with ozone, and creating a vacuum in the refrigeratorcompartment. Low temperature and humidity may reduce microbial activity,but may require increased energy consumption, may not be desirable forcertain foods because low temperature and humidity tend to dehydratefood, and may not entirely eliminate microbial activity. Ozone is onlyeffective for microbial control at concentrations that are harmful tohuman health. In addition, ozone is a greenhouse gas; the release ofozone into the atmosphere is harmful to the environment. Vacuumrefrigerators require vacuum pumps to pull air out of the refrigeratorcompartments and require a vacuum seal, which are expensive. Inaddition, vacuum conditions tend to dehydrate food. Conventional metalvapor-based ultraviolet emission sources such as mercury bulbs sufferfrom low efficiency in refrigerators due to reduced vapor pressureinside the bulb. Their manufacture and disposal are harmful to theenvironment. Breakage of such bulbs inside a refrigerator may cause foodand home contamination.

SUMMARY

Embodiments of the invention include a sealed compartment and a doordisposed on a side of the sealed compartment, and a cooler for coolingan interior of the sealed compartment. At least one light emitting diodeconfigured to emit light having a peak wavelength in the ultravioletrange is positioned to emit ultraviolet light in the sealed compartment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a compartment including a cooler and a UV lightemitting diode.

FIG. 2 illustrates several examples of how UV LEDs may be incorporatedinto a refrigerator.

FIG. 3 is a front perspective view of an air circulation hub for arefrigerator.

FIG. 4 is an exploded view of the air circulation hub illustrated inFIG. 3.

FIG. 5 is an exploded view of a shelf with UV LEDs.

FIGS. 6A, 6B, and 6C illustrate translational scanning, rotationalscanning, and combined translational and rotational scanning.

FIG. 7 is an exploded view of a movable stage which may be used forscanning.

FIG. 8 illustrates an arrangement of shelves and an air circulation hubin a sealed compartment.

DETAILED DESCRIPTION

In embodiments of the invention, a refrigerator includes at least onelight emitting diode that emits UV light into the refrigeratedcompartment. The UV light may reduce or eliminate the growth of microbesin the refrigerator.

FIG. 1 is a simplified view of refrigerator according to embodiments ofthe invention. A sealable compartment 10 includes a door 14 disposed onat least one side to allow access to compartment 10. A seal may bedisposed between door 14 and the rest of compartment 10. A cooler 12 maybe used to cool the interior of compartment 10. Compartment 10 may beinsulated. Any or all of the interior walls of compartment 10, includingtop, bottom, and side walls, may be UV-reflective material or coatedwith a UV-reflective material. Compartment 10, door 14, the seal betweendoor 14 and compartment 10, and cooler 12 may be any suitable structureand are well known in the art. At least one ultraviolet (UV) LED 16 isdisposed such that UV LED 16 may emit UV light in compartment 10. UV LED16 is connected to a power source and may be connected to controlcircuitry as is known in the art.

UV LED 16 may be any suitable device that emits radiation at awavelength that is able to disinfect the air or other fluid flowing overthe UV LED. In some embodiments, UV LED 16 emits radiation with a peakwavelength less than 300 nm. In some embodiments, UV LED 16 isconfigured to emit light over broad angles, for example in a cone of atleast 120°, such that UV radiation is emitted into as much of the volumeof the chamber in which the UV LED is disposed as possible. The emissionpattern may be controlled through optics, lenses, or reflectorsconnected to the device structure of UV LED 16 or to a package in whichthe device structure of UV LED 16 is disposed, as is known in the art.UV LED 16 is often disposed in a chamber and surrounded by reflectivematerials, such that little or no UV radiation is able to escape thechamber.

FIG. 2 illustrates several examples of how UV LEDs may be incorporatedinto a refrigerator, according to embodiments of the invention. UV LEDsmay be included in an air circulation hub 22 which circulates air withinsealed compartment 10. Air circulation hub 22 is illustrated in moredetail in FIGS. 3 and 4. UV LEDs may be included on or in a shelf 20 onwhich food or other material is stored in sealed compartment 10. Shelf20 is illustrated in more detail in FIG. 5. UV LEDs may be included in amovable stage 24 positioned to emit UV light into sealed compartment 10.Movable stages 24 are illustrated in more detail in FIGS. 6A, 6B, 6C,and 7. UV LEDs may be included in a portion of a drawer 26 or othercompartment. The drawer 26 may be removable from the refrigerator andused separate from the refrigerator as a disinfectant box. The drawer 26may include a self-contained battery source to power the UV LEDs in thedrawer, or the drawer 26 may include structures that draw electricalcurrent from a power source outside the refrigerator to which therefrigerator is connected such as a wall plug. A refrigerator mayinclude only one of the examples illustrated in FIG. 2 or may includemultiple examples.

FIG. 4 is an exploded view of the air circulation hub 22 shown in aperspective view in FIG. 3. Air circulation hub 22 includes a cover 36that connects to a body 46, for example by friction fit, by glue, byscrews, or any other suitable fastening method or fastener. Positionedbetween the cover 36 and body 46 is a fan box 44 which includes a fanfor circulating air. The fan box 44 is covered by a filter 42, which maybe any suitable filter such as a high efficiency particulate air (HEPA)filter.

A module 48 which includes one or more UV LEDs is attached to cover 36,or to body 46. Module 48 may be, for example, a rigid or flexiblecircuit board on which one or more UV LEDs are mounted. Wiring may beformed on module 48 to electrically connect the UV LEDs to each other,for example, to other circuitry such as power conditioning orelectrostatic discharge protection circuitry, and/or to a power source.

A face plate 30 attaches to cover 36, for example by friction fit, byglue, by screws, or by any other suitable fastening method or fastener.An opening 32, which may be a circular gap between face plate 30 andcover 36 as illustrated in FIG. 3 or any other suitable opening, allowsair to flow into the air circulation hub 22. Any suitable shape, number,and size of openings 32 may be used. Indicators 38 may be disposed on orwithin face plate 30. Any suitable indicator 38 may be used, such asorganic LEDs or semiconductor LEDs that emit visible light. Indicators38 may provide visual cues, for example indicating that the refrigeratoris cooling, and/or warnings, for example indicating that the UV LEDs onmodule 48 are emitting UV light.

Face plate 30 may position a circuit board 40 in contact with module 48.Circuit board 40 may include, for example, driver circuitry for the UVLEDs on module 48, timing circuits for timed operation of the UV LEDs,circuitry for a refrigerator door safety interlock, and/or drivercircuitry for indicators 38. A refrigerator door safety interlockcircuit may include a sensor that senses when the door is open and acircuit that prevents power from being supplied to the UV LEDs when thedoor is open.

FIGS. 3 and 4 illustrate just one example of an air circulation hub 22.The components in the air circulation hub may be arranged differentlyfrom what is illustrated in FIGS. 3 and 4, more or fewer components maybe included in the air circulation hub, and the air circulation hub mayhave a different appearance than is illustrated in FIGS. 3 and 4.

In operation, a fan in fan box 44 draws air into the air circulation hubthrough opening 32 illustrated in FIG. 3. The air flows into a chamberformed between cover 36 and body 46 which is irradiated with light fromthe one or more UV LEDs on module 48, disposed on one side of thechamber. The interior of the chamber formed between cover 36 and body 46may be coated with UV reflective material. Examples of suitableUV-reflective material include aluminum and palladium. A reflectivecoating may be plated, sputtered, or evaporated directly on the walls ofthe chamber, or the reflective coating may be a foil or a film attachedto the surfaces of cover 36 and body 46 that form the walls of thechamber. Radiation emitted by UV LEDs is reflected by the reflectivecoating such that all or nearly all of the chamber formed by cover 36and body 46 is filled with UV radiation. Accordingly, little or no airpasses through the chamber without being exposed to UV radiation.

The chamber may include a structure to encourage mixing of the air. Thestructures may mix the incoming air and prevent laminar flow of the air,which may (1) effectively lengthen the trajectory of air within thechamber, and (2) allow air to pass closer to the surface of the LEDswhere the radiation has the highest intensity, causing more exposure tostronger UV radiation, which may result in purer air. Examples ofsuitable structures include baffles, vanes, or other protrusions on theside walls of the chamber or within the chamber. Alternatively, thechamber can be divided into several serpentine passages to extend thedistance air must travel before leaving the chamber, causing moreexposure to UV radiation, which may result in purer air. Serpentinepassageways may be formed by forming passageway walls on one or both ofcover 36 and body 46, such that when cover 36 and body 46 are pressedtogether to form the chamber, sealed or nearly sealed passageways areformed. As the air encounters light from the UV LEDs, any pathogens inthe air are killed by the UV radiation, such that the air isdisinfected. The fan draws the irradiated air through filter 42, whichfilters out some or all particulate matter in the air. The air may thenexit the back of body 46. Air exiting air circulation hub 22 may bevented into the sealed compartment 10 of the refrigerator or outside thesealed compartment 10 of the refrigerator.

In the refrigerator illustrated in FIG. 2, the air circulation hub 22illustrated in FIGS. 3 and 4 is mounted on a back wall of sealedcompartment 10. Though only one air circulation hub 22 is illustrated,multiple air circulation hubs may be used in a single refrigerator, andone or more air circulation hubs may be used in a single compartment ina refrigerator with multiple compartments. In a refrigerator including adrawer that may be removed from the refrigerator and used as a separatecompartment, the removable drawer may include an air circulation hubthat is powered, for example, by a battery that may be recharged whenthe removable drawer is replaced in the refrigerator.

FIG. 5 illustrates a shelf 20 including UV LEDs 16. UV LEDs 16 may beembedded within or disposed on a surface of the shelf. In onearrangement, UV LEDs 16 are disposed on a module 50, which is thencovered with a UV-transparent cover 51. Examples of suitable UVtransparent covers include quartz or glass plates. The cover may serveas the surface on which food or other materials stored in therefrigerator are placed, or a shelf on which food or other materialsstored in the refrigerator are placed may be spaced apart from thecover, as described below in reference to FIG. 8. UV LEDs 16 in FIG. 5are arranged in a 4 x 3 rectangular array. More or fewer UV LEDs 16 maybe used, and the UV LEDs 16 may be arranged in any suitable arrangement.The materials surrounding UV LEDs 16, such as the top surface of module50 between neighboring UV LEDs, may be chosen to withstand and reflectUV rays. Examples of suitable materials include any of the reflectivematerials described above, barium sulfate, and Teflon. In someembodiments, UV LEDs 16 are connected to a structure that facilitatesheat transfer from the UV LEDs to the surrounding environment, such asmetallic heat sinks. Transferring heat away from UV LEDs 16 may improvethe efficiency of the UV LEDs and may extend the lifetime of the UVLEDs.

In some embodiments, UV LEDs are disposed on or in the shelf orientedsuch that UV light shines both up from the top of the shelf and downfrom the bottom of the shelf. The shelf may include visible indicatorssuch as organic LEDs or LEDS that emit visible light and which indicatewhen the UV LEDs are emitting light. Circuitry such as electrical drivercircuitry for UV LEDs 16, driver circuitry for indicators, timingcircuits which dictate when UV LEDs 16 emit UV light, and/or safetyinterlocks may be included in module 50, for example, or on one or moreother structures disposed inside shelf 20 or inside a frame supportingshelf 20.

In some embodiments, UV LEDs are mounted in a movable stage that changesthe area that is irradiated with UV light as a function of time. FIGS.6A, 6B, and 6C illustrate examples of the types of scanning that can bedone by movable stages. In FIG. 6A, the movable stage 24 moves along anaxis and irradiates the area beneath the scanning device, as illustratedby the cones. In FIG. 6B, the movable stage rotates and irradiatesdifferent areas along the axis of rotation. In FIG. 6C, the movablestage moves along an axis and rotates. Other ways of changing the areathat is irradiated as a function of time may be used.

FIG. 7 is an exploded view of a movable stage 24 capable oftranslational scanning, as illustrated in FIG. 6A. The movable stage ofFIG. 7 includes a housing 60 which houses one or more axles 64 connectedto wheels 62. Axles 64 may connect to housing 60 through holes 61 formedin either end of housing 60. Axles 64 are connected to a motor 66capable of moving housing 60 by turning axles 64. Motor 66 isillustrated in the center of housing 60, though motor 66 may be mountedin any suitable location. One or more UV LEDs 16 is attached to a frame68 which is disposed in housing 60 beneath axles 64. Frame 68 may be,for example, a circuit board, which may also include, for example,driver circuitry for LEDs 16, timing and/or driver circuitry foractivating motor 66 to move stage 24, circuitry for a refrigerator doorsafety interlock, and any other required circuitry. A cover 70 protectsUV LEDs 16 and includes a window 72 that is transparent to UV light.

In operation, wheels 62 may rest on tracks positioned in the sealedcompartment 10. Motor 66 turns axles 64 and wheels 62 such that theframe 68 and UV LEDs 16 roll along the tracks. The movable stageillustrated in FIG. 7 may also be used for rotational scanning asillustrated in FIG. 6B. Wheels 62 and axles 64 may be omitted from arotational scanning device. A motor capable of turning housing 60 may bemounted on the top of housing 60 in the center. Such a rotationalscanning device may be used for translational and rotational scanning asillustrated in FIG. 6C be attaching the motor capable of turning housing60 to one or more axles connected to one or more wheels capable ofrolling along a track.

FIG. 2 illustrates a movable stage 24 mounted such that the UV LEDs emitlight in a generally downward direction. In some embodiments, movablestages that emit light upward can be disposed on the bottom of thesealed compartment 10, or movable stages that emit light to the side canbe disposed on one or more sides of the sealed compartment 10. Movablestages may be separated from the sealed compartment 10 by a UVtransparent cover or may be embedded within the top, bottom, and/orsides of the sealed compartment.

FIG. 8 illustrates an arrangement of shelves in sealed compartment 10which may avoid the placement of food or other materials in sealedcompartment 10 in areas that cannot be reached by purified air emittedfrom air circulation hub 22 or by UV light from UV LEDs that emit lightdirectly into the sealed compartment. As described above, the top 80,sides 82, and bottom 84 of sealed compartment 10 are oftenUV-reflective. In some embodiments, the UV reflective material on thetop, sides, and bottom of sealed compartment 10 acts as a diffusereflector. A surface of food or other material placed in direct contactwith these surfaces cannot be reached by the air emitted by aircirculation hub 22 or by UV light from UV LEDs that emit light into thesealed compartment. Accordingly, in some embodiments, shelves 86 for thestorage of food or other materials are spaced apart from the bottom 84of sealed compartment 10 by a gap 88. Shelves 86 may be wire or othermaterials that do not significantly occlude the bottom surface ofmaterials placed on the shelf, or a solid UV transparent material. Insome embodiments, a face plate or other structure that preventsmaterials from being placed in gap 88 is positioned between bottom 84and shelf 86. In some embodiments, shelves 86 include protrusions 90which prevent materials from being placed in contact with the sidesurfaces of sealed compartment 10.

Gaps 88 and 90 allow UV light or UV-purified air coming from above shelf86 to reflect off bottom surface 84, which may increase the likelihoodthe bottom surface of materials on shelf 86 is exposed to UV light or UVpurified air.

Having described the invention in detail, those skilled in the art willappreciate that, given the present disclosure, modifications may be madeto the invention without departing from the spirit of the inventiveconcept described herein. Therefore, it is not intended that the scopeof the invention be limited to the specific embodiments illustrated anddescribed.

What is being claimed is:
 1. An apparatus comprising: a sealedcompartment; a door disposed on a side of the sealed compartment; atleast one light emitting diode configured to emit light having a peakwavelength in the ultraviolet range positioned to emit ultraviolet lightin the sealed compartment; and a cooling device to cool an interior ofthe sealed compartment.
 2. The apparatus of claim 1 further comprisingan ultraviolet-reflective material disposed on a sidewall of the sealedcompartment.
 3. The apparatus of claim 1 further comprising a fan tocirculate ambient gas in the sealed compartment.
 4. The apparatus ofclaim 1 wherein the at least one light emitting diode is disposed on amovable stage.
 5. The apparatus of claim 4 further comprising controlcircuitry configured to move the movable stage.
 6. The apparatus ofclaim 1 further comprising a drawer disposed within the sealedcompartment, wherein: the at least one light emitting diode ispositioned to emit ultraviolet light in the drawer; and the drawer isremovable from the sealed compartment.
 7. The apparatus of claim 1further comprising control circuitry connected to the at least one lightemitting diode, wherein the control circuitry is configured toperiodically activate the at least one light emitting diode.
 8. Theapparatus of claim 1 further comprising an indicator that indicates whenthe at least one light emitting diode is forward biased.
 9. Theapparatus of claim 1 wherein the at least one light emitting diode isdisposed in an air circulation hub, the air circulation hub furthercomprising: a cover; a body, wherein the at least one light emittingdiode is disposed between the cover and the body; an opening in thecover; a fan disposed between body and the at least one light emittingdiode; and a filter disposed between the fan and the at least one lightemitting diode.
 10. A method comprising: providing a structurecomprising: a sealed compartment; a door disposed on a side of thesealed compartment; and at least one light emitting diode configured toemit light having a peak wavelength in the ultraviolet range positionedto emit ultraviolet light in the sealed compartment; and cooling aninterior of the sealed compartment to a temperature below ambienttemperature.
 11. The method of claim 10 wherein the at least one lightemitting diode is mounted on a movable stage, the method furthercomprising moving the movable stage.
 12. The method of claim 11 furthercomprising activating the at least one light emitting diode while movingthe movable stage.
 13. The method of claim 10 further comprisingactivating a fan positioned to circulate ambient gas within the sealedcompartment.